On Sol 12, Curiosity used her instrument DAN (Dynamic Albedo of Neutrons) to start an experiment called “Active Neutron Sounding”. DAN is a neutron spectrometer and able to measure the abundance of hydrogen on Mars.
It uses a 14 MeV source to blast a neutron stream to the ground and measures the time decay curve of the neutron flux from the subsurface. Here’s a diagram showing the result of this first experiment (red line) compared to a pre-launch test (blue line):
This first test showed the instrument to be in perfect condition to later go on search for water on Mars. Hydrogen is an indicator of water and Curiosity will use this experiment to look for water content at different spots on it’s route, down to about one meter (3.3 feet) below the surface.
DAN consists of two parts, the neutron generator (DAN ping) and the detector. Here’s an image of Curiosity, showing the position of the two modules:
What’s your thoughts about this? What will Curiosity find? Let me know in the comments!